Rotary fluid pressure engine and the like



Dec. 5, 1939. BOOTH 2,182,719

ROTARY FLUID PRESSURE ENGINE AND THE LIKE Fi led Aug. 26, 193 7 2 Sheets-She et 1 g0 17 21 28 12 n /'V \I A A l 22 24 23 V I8 3 a V4 1 2-27. 22 T 2 AT 25 5 k a 6 v "7 'l 22 24 8 x Q -11 28 Fig. 2. 28 3 4-fk/l INVENTOI? Y rncst' 500th Dec. 5, 1939. v BOOTH 2,182,719

ROTARY FLUID PRESSURE ENGINE AND THE LIKE Filed Aug. 26, 193'? '2Sheets-Sheet 2 4 ATTORNEY 8 ErneSUBw'th Patented Dec. 5,1939

' UNITED STATES PATENT OFFICE ROTARY FLUID PRESSURE ENGINE AND THE LIKEGreat Britain Application August 26,

1937, Serial Nn- 16 ,95

In Great Britain September s, i335 13 Claims.

This invention relates to rotary fluid pressure engines, pumps, motors,meters and the like adapted to be operated by or to operate upon afluid, hereinafter termed the working fluid, and

: whether employed primarily to .act on or to be operated by the workingfluid or employed as or incorporated in devices, such as transmissiondevices.

For brevity, such engines, pumps, motors, meters and the like ,will bereferred to herein as rotary engines.

This invention concerns rotary engines of the kindcomprising memberswhich enclose between theman annular bladechamber and are rotatablerelatively .to one another about the axis of the blade chamber, at leastoneabutment fixed to one of the-members and extending across the chamberbetween inlet and outlet ports and. blades whichare peripherallypart-circular in cross-sec- .tionand rotate continuously about their ownaxes in recesses in one of the radially opposed peripheries of thechamber, this periphery being carried upon the other member, and are soshaped that .during relative rotation of the members each blade projectsacross the blade chamber and makes a sealing fit with the oppositeperiphery as the blade passes through the part orparts of the chambernotoccupied by an abutment but recedes into and is wholly contained in itsrecess during its passagepast the abutmentor abutments. It will beunderstood that since each blade must be wholly contained in its recessas it passes an abutment there will be a transitional period immediatelybefore and after each blade passes an abutment during which it isrespectively receding into its recess and emerging from it and does nottherefore make a sealing fit with the opposite periphery of the bladechamber although it is passing through parts of the blade chamber notoccupied by an abutment.

Theper'iphery in which the blade recesses are formed will be hereinaftertermed the bladehousing periphery and the opposite periphery will betermed the blade-sealing periphery. Further, each part of a blade whichlies between peripherally circular sealing parts and constitutes agap inthe peripherally circular surface of the blade to permit passage past anabutment will be referred to as a non-sealing part of the blade. It willalso be assumed in describing the invention that the member carrying theabutment or abutments j is stationary and that carrying theblade-housing periphery rotatesbut it is to be understood that theinvention is applicable to other arrangements in which relative rotationtakes place between the two members.

With rotary engines of the general kind re- --ferred toabove, employingas hitherto blades of approximately segmental cross-section, it is im- Aitces to ha the-' pn-. a ine t r rt of the blades so as to conform withthe surface of the abutment's adjacent to which they pass Inconsequence, in the case of a pump or'compressor apart of the'workingfluid is transferred by the space thus left from the delivery or highpressure side of the abutment to the inlet orlow pres sure side. Asimilar effect may also take place due to the fact that during thepassage of the blade through the part of the blade chamber not occupiedby the abutment (hereinafter referred to as the swept part of the bladechamber) the blade does not completely fill the recess'in which itrotates but a space is left therein by the nonsealing part or parts ofthe blade, this space communicating first with the inlet side of the'blade chamber and then, after'being closed to both sides thereof, withthe outlet side. This, in' the case of an engine or motor, results in acertain degree of transference of working fluid from the high to the lowpressure side of the blade, andin the case of a pump a sudden rush ofworking fluid 'into the space as it comes into communication with thehigh pressure side of the blade chamher, which may produce a certaindegree of back pressure effect.

The object of the present invention is to provide certain improvementsin rotary engines of the-kind referred to which will reduce or eliminatethe above difliculties.

To this end according to the present invention the-blades ofa-rotaryengine of the kind referred .to are of-part annular cross-section andthe recesses in the bladehousing peripheryare similarlyofpart-annular.cross-section, that is .to say -in-the form ofvpart-annular slots which accom- -m0date ,the blades as they pass theabutment or abutments but from which they emerge during theirrotationabout their own ax es relatively tothe b lade-housing periphery to makean approximately fiuid-tight seal with the blade-seal-v mg periphery.

In this way the .width of the dead space between each blade andthesurface of an abutment adjacent towhich it passes, is confined to thewidth of, the. ends ,ofthepart-annular slot in which the chamber is lessthan with' the previous form of blade so that difiiculties due to thefact that this unoccupied portion of the recess isbrought successivelyintov communication with the inlet and outlet portions of thebladechamber are cor-' respondingly reduced.

Preferably the blade sealing periphery is formed or carried .on thesamemember as the .bl wheniea i e O h the W 2 blade rotates instead ofextending over the whole through the swept part or parts of the blade".

ripheries rotate together. In this case, the

blade-sealing periphery is provided opposite each blade recess with agroove having a part-circular surface of the same centre and radius ofcurva-' ture as the outer surface of the blade recess so as to make aseal with the part-circular surface of the blade when the blade extendsacross the blade chamber. It will be seen that with this arrangementeach blade recess and the groove may be made in a single turningoperation, the groove in fact forming in effect a part of the outersurface of the blade recess where this outer surface, after beinginterrupted by the blade chamber, cuts into the blade-sealing periphery.This arrangement not only provides area sealing between the blades andthe bladesealing periphery but also has the advantage that it rendersunnecessary complete accuracy in the positioning of the axes of theblades since slight inaccuracies will merely result in a slightly wideror narrower groove without affecting the obtaining of a substantiallypressure-tight fit between the blades and the bladesealing periphery.

In rotary engines of the kind referred to the blades conveniently rotaterelatively to the bladehousing periphery in a direction opposite to thatin which this periphery rotates. With the present invention when theleading edge of a partannular blade has passed the leading edge of anabutment, a portion of working fluid becomes trapped in the open end ofthe annular slot in which the blade moves and the continued movement ofthe blade tends to compress this trapped fluid. Further, in anoil-lubricated gaseous fluid engine, lubricating oil may be similarlytrapped. In order to meet this difficulty according to a further featureof the invention, as is more particularly desirable when the workingfluid is substantially incompressible, provision may be made for placingthe leading end of each blade recess, as it passes an abutment, firstinto communication with the outlet side of the blade chamber and then,when the trailing end of the blade recess has passed the leading edge ofthe abutment, into communication with the trailing end of the bladerecess. In this way, the building up of excessive pressure in the recessby the advancing end of the blade is prevented and substantialequalisation of the pressure acting respectively on the leading andtrailing edges of the blade is ensured. For example, the radius ofcurvature of the periphery of the concentric member in which the bladerecesses are formed may be made slightly less between the two ends ofeach blade recess than over the remaining portions of the said peripherywhich effects a seal with the abutment. Alternatively, the same resultmay be obtained by the use of suitable slots or ports.

An important incidental advantage of the invention is that since theconcentric member in which the blades rotate has portions which extendaxially into the part-annular blades and form the inner walls of theannular blade recesses, the bearings for supporting these blades may liein these portions and can therefore be of needle or elongated rollertype without unduly increasing the overall axial length of the engine.

The invention may be carried into practice in various ways but oneconstruction according to the invention is shown somewhatdiagrammatically by way of example in the accompanying drawings whichalso show a modification of the invention and include diagrammatic viewsto illustrate the general principle of the invention.

In the accompanying drawings Figure 1 is a longitudinal axial sectionthrough one construction of rotary engine according to the invention,

Figure 2 is a cross-section through the engine shown in Figure 1 takenon the line ]III of Figure Figures 3, 4 and are diagrammatic views forthe purpose of illustrating more clearly the general principle of theinvention, and

Figure 6 illustrates a constructional modification of the invention.

In the construction illustrated in Figures 1 and 2 the engine, which isof the same general con struction as that described with reference toFigures and 11 in the specification of United States of America patentapplication Serial No. 88,231, comprises a generally cylindrical rotor Iand a stator 2. The stator 2 comprises end walls 3 and 4 through one ofwhich passes a power shaft 5 rigidly connected to the rotor andsupported in a ball bearing 6 while the other carries a ball bearing 1for supporting the other end of the rotor, as shown.

Formed in the rotor I and concentric therewith are two annular recesses8 and 9 extending into the rotor from opposite ends thereof andconstituting annular blade chambers. the stator casing 2 into eachannular chamber between an inlet Ill and an outlet II for working fluidis an abutment, these abutments being designated by the referencenumerals I2 and I3. The inner part of the rotor I, that is to say thepart forming the inner walls of the recesses 8 and 9, is provided with apair of recesses I4 and I5 of part-annular cross-section the axes ofwhich are parallel to one another and to the axis of rotation of therotor I and are formed as shown. The axial length of the recesses I4 andI5 is substantially equal to the distance between the outer end wall ofthe blade chamber 8 and the outer end wall of the opposite blade chamber9 and moving within each recess is a blade I6 of part-annular sectionthe axial length of which is substantially equal to the said axiallength of the recesses I4 and I5. It will thus be seen that the innerpart of the rotor I forms the blade-housing periphery. Each blade I 5 isformed with a central web I! which serves to connect the part-annularperipheral portion of the blade to a blade shaft I8 the end portions ofwhich lie in tunnels 22 in the central portion of the rotor. Theperipheral surface of each web I1. is circular where it extends throughthe gap in the circumference of the blade and has a radius of curvatureequal to that of the outer periphcry of the blade. Further, the part ofeach web which extends through the gap in the blade may be solid whilethe part lying between the shaft I8 and the blade may be hollow, so asto provide for dynamic balance of the blade as it rotates around theaxis of its shaft.

As will be understood, the rotor I is provided with short cylindricalrecesses I9 to receive the webs II, the axial length of these recessesbeing substantially equal to the axial length of the webs.

Each blade shaft I8 is provided with a pair of needle type rollerbearings 20, 2I disposed in the cylindrical tunnels 22 in the centralportion of the rotor I and also with a ball bearing 23 constituting anadditional support.

The blade shafts and with them the blades Extending from are arranged torotate in the rotor about their own axes in a direction opposite to thatin which the rotor rotates and in such a manner that each.

secured to the blade shafts la, a fixed sun wheel 25 mounted on thestator casing Z and a pair of intermediate gear wheels 26, 21 eachmeshing with ,one of the planet wheels Ziand with the sun wheel 25.Other forms of gearingor other j mechanisms may, however, be employedinstead of that described for causing the desired rotation of the bladesin their recesses about their own axes as therotor revolves.

Formed in the outer periphery of each blade chamber opposite each bladerecess, that is to say in the blade-sealing periphery, is an axiallyextending channel 28 the surface of which is concentric with the bladerecesses l4, l5 and forms in effect a continuation or part of the outersurface of the blade recess so that the outer periphery of the blade, asit passes during rotation over thesurface of the channel will maketherewith a fine-clearance sealing fit. Thus, in turning the bladerecesses, the channels are automatically formed and it will beseen thatin this way satisfactory sealing between the blades and theblade-sealing periphery can be obtained without the necessity forensuring complete accuracy in the positions of the blade axes andmoreover that area sealing is obtained between the blade and the outeras well as. the inner periphery' of the blade chamber with theconsequent advantages of such form of sealing over line sealing.

' It will be appreciated that the other relatively moving surfaces ofthe engine which in operation effect a sealing fit conveniently effect afine-clearance sealing fit. Thus, the inner. peripheries of the bladechambers 8'and 9 conveniently effect 'a fine-clearance sealing fit withthe inner faces of the abutments l2 and I3 and similarly the outerperipheries of the blade chambers effect a fine-clearance sealing fitwith the outer surfaces of the abutments. ends 'of the abutmentsconveniently effect a fine-clearance sealing fit not only .with the webIT but with the central web portion of the rotor which extends radiallyin the plane of the web l'i between the adjacent ends of the bladechambers 8 and 9.

Similarly, the outer circumferential surface of the rotor effects afine-clearance sealing fit with the surrounding portion of the statorcasing 2.

Referring to Figures 3, 4 and 5, which are cross-sections of engines ofthe kind referred to through the rotor, the abutment and one blade,Figure 3 shows an arrangement in which, as hitherto, the blades are ofapproximately segmental form as applied to a construction in which thestator casing forms the outer peripheryof the blade chamber and theblades thus make a fine-clearance line sealing fit with this outerperiphery as they rotate in their recesses and bodily with the rotor.

In this construction the'rotor is designated i the stator 2 the inletand outlet ports w and H respectively, the annular blade chamberB theabutment l2 and the blades |6*--. It willbe seen that in theconstruction illustrated inFigure 3, which shows the rotor in theposition. in which a blade is passing the abut-- For this purposeepicyclic' Again, the opposed ment 12 there is a considerable volume ofdead space in the blade recess between the non-sealing part of the bladeand the surface of the abutment.

F-igures4 and 5 show respectively two positions of the rotor in aconstruction according to the invention as illustrated in Figures land2.

Thus Figure 4 shows the rotor at a corresponding position to that shownin Figure 3 and it willbe seen that with the construction according tothe invention the dead space left in the blade recess is veryconsiderably less, being limited to the two end portions of the annularrecess 14.

Figure 5 shows the rotor in the position in which the leading end of theblade recess has passed the leading edge of the abutment 12 while thetrailing end of the blade recess is still in the blade chamber.continued rotation of therotor into the position shown in Figure 3', themovement of the blade will tend to compress fluid between its leadingedge and the abutment [2. In order to overcome this difficulty, one ormore shallow grooves 30 may be formed between the ends of each bladerecess orthe radius of curvature of the surface of the recess may beslightly reduced to provide an escape channel. This channel forms apassage through which working fluid can escape from the space in theblade recess in front of the advancing edgeof the blade. It will be seenthat the channel 30 will communicate with the outlet side of the bladechamber until cut off by the portion of the periphery of the rotorimmediately behind the trailing end of the blade recess, after which anduntil'the'leading end of the recess passes from the trailing edge of theabutment, the channel 30 can serve as a transfer passage along whichfluid can pass from one end of the blade recess to the other.

In order to increase the efficiency of a rotary engine according to theinvention, more particularly where the operating fluid is compressible,as in the case of an air compressor, a non-return check valve may, ifdesired, be fitted in the outlet from the blade chamber, this checkvalve being preferably arranged as near to the outlet end of the bladechamber as possible. In this way back pressure which would otherwiseoperate on the blades throughout the major portion of their effectivetravel around the blade chamberwill be cut off by the non-return valvewhich will, how ever, open automatically as the fluid in front of eachblade reaches the requisite pressure to permit such fluidto pass to theoutlet.

Figure 6 illustrates such a modification of the invention as applied toa construction which may be generally similar to that illustrated inFigures 1 and 2. Thus, in Figure 6, a non-return valve, indicated at 31,is arranged in the outlet passage 11.

Figure 6 also illustrates a modification designed to provide a highercompression ratio when operating with or upon air or like compressibleworking fluid and when employing a non-return valve such as thatreferred to above. In this construction the side of the abutmentadjacent to the outlet H is extended, as shown at 32, and given an innercontour over this extended part which conforms approximately to the pathtraversed by'the rear edge of each blade after it has broken the sealwith the outer periphery of the blade chamber preparatory to passing theabutment. In this way, it will be seen that the volume of fluid betweeneach blade and the abutment immediately before the blade breaks sealwiththe outer periphery of the'blad e'chamber It will be seen thatduring v is reduced and the compression ratio thus increased.

It is to be understood that the present invention may be applied torotary engines of the kind described in the specifications of UnitedStates of America patent applications Serial Nos. 88,231 and 88,232, inwhich means are provided for varying the effective length of the bladechamber and thereby the capacity of the engine.

It is also to be understood that the construc tional forms of theinvention may vary considerably. For example, in a constructiongenerally similar to that shown in Figures 1 and 2, the channels 28 maybe omitted and the peripheries of the blades may make a line sealing fitwith the outer periphery of the blade chamber. Where high volumetricefficiencies are desired, however, it is usually preferable to providethe channels which thus give area sealing as between the blades and theouter periphery of the blade chamber.

Where the invention is applied to a power transmission device, it willbe appreciated that the said device, if for use as a slipping clutch,may comprise a single rotary engine according to the invention withmeans for restricting or closing the outlet at will, while, if for useas a torque converter, may comprise two rotary engines according to theinvention coupled together so that the fluid delivered by oneconstituting a pump is supplied to the other, operating as a motor, withor without means for varying the capacity of one or each of the rotaryengines for the purpose of varying the torque or speed ratio transmittedby the device. Further, it will be appreciated that the rotor, statorand other parts may be built up in various ways as may be foundconvenient.

What I claim as my invention and desire to secure by Letters Patent is:

l. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of this blade chamber, at least one abutment rigid with one ofthe members and extending across the blade chamber be tween inlet andoutlet ports which are stationary with respect to the abutment, bladeseach of which is of part-annular cross-section and is rotatably disposedin a part-annular recess in one of the radially opposed peripheries ofthe blade chamber with its axis of rotation lying within said oneperiphery, said one periphery being carried by the member not carryingthe abutment, each blade being of such dimensions as at all times to lieat least partly within its part-annular recess but being capable ofprojecting across the blade chamber to make an approximately fluidtightseal with the opposite periphery or of lying wholly within its recessaccording to its rotational position, and means for causing continuousrotation of the blades in their recesses during relative rotation of thetwo members and in such timed relation to the relative rotation of thesetwo members that each blade projects across the blade chamber as itpasses through the part of the blade chamber not occupied by an abutmentbut recedes into and is wholly contained in its recess during itspassage past the abutment.

2. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of that blade chamber, the two radially opposed peripheries ofthe blade chamber being constituted by parts of one of the two members,at least one abutment rigid with the other of the two members andextending across the blade chamber between inlet and outlet ports whichare stationary with respect to the abutment, blades each of which is ofpart-annular cross-section and is rotatably disposed in a part-annularrecess vin one of the radially opposed peripheries of the blade chamberwith its axis of rotation lying within that periphery, this peripherybeing carried by the member not carrying the abutment, each blade beingof such dimensions as at all times to lie at least partly within itspart-annular recess but being capable of projecting therefrom across theblade chamber to make an approximately fluid-tight seal with theopposite periphery or of lying wholly in its recess according to itsrotational position and means for causing continuous rotation of theblades in their recesses during relative rotation of the two members andin such timed relation to the relative rotation of these two membersthat each blade projects across the blade chamber as it passes throughthe part of the blade chamber not occupied by an abutment but recedesinto and is wholly contained in its recess a during its passage past theabutment.

3. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of that blade chamber, the

two radially opposed peripheries of the blade chamber being constitutedby parts of one of the two members, at least one abutment rigid with theother of the two members and extending across the blade chamber betweeninlet and outlet ports which are stationary with respect to theabutment, blades each of which is of part-annular cross-section and isrotatably disposed in a part-annular recess in one of the radiallyopposed peripheries of the blade chamber with its axis of rotation lyingwithin that periphery, this periphery being carried by the member notcarrying the abutment, each blade being of such dimensions as at alltimes to lie at least partly within its part-annular recess but beingcapable of projecting across the blade chamber to make an approximatelyfluid-tight seal with the opposite periphery or of lying wholly in itsrecess according to its rotational position, the periphery of the bladechamber opposite each blade recess being provided with a groove whosesurface is concentric with and has the same radius of curvature as theouter surface of the blade recess so as to provide area sealing betweenthe outer surface of the blade and this groove, and means for &

causing continuous rotation of the blades in their recesses duringrelative rotation of the two members and in such timed relation to therelative rotation of these two members that each blade projects acrossthe blade chamber as it passes through the part of the blade chamber notoccupied by an abutment but recedes into and is wholly contained in itsrecess during its passage past the abutment.

4. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of this blade chamber, at least one abutment rigid with one ofthe members and extending across the blade chamber between inlet andoutlet ports, blades each of which is of part-annular cross-section andis rotatably disposed in a part-annular recess in one of the radiallyopposed peripheries of the blade chamher, this periphery being carried,by the member not carrying the abutment, each blade being capable ofprojecting across the blade chamber to make an approximately fluid-tightseal with the opposite periphery or of lying wholly within its recessaccording to its rotational position, means for causing continuousrotation of the blades in their recesses during relative rotation of thetwo members so that each blade projects across the blade chamber as itpasses through the part of the blade chamber not occupied by an abutmentbut recedes into and is wholly contained in its recess during itspassage past the abutment, and means for placing the leading end of eachblade recess, during its passage past an abutment, first incommunication with the outlet side of the blade chamber and then, whileboth ends of the recess lie opposite the abutment, in communication withthe trailing end of the recess.

5. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of that blade chamber, the

two radially opposed peripheries of the blade chamber being constitutedby parts of one of the two members, an abutment rigid with the other ofthe two members and extending across the blade chamber between inlet andoutlet ports, blades of part-annular cross-section rotatably mounted inpart-annular recesses in one of the radially opposed peripheries andeach capable of projecting therefrom across the blade chamber to make asubstantially fluid-tight seal with the other periphery or of lyingwholly in its recess according to its rotational position, means forcausing continuous rotation of the blades in their recesses duringrelative rotation of the two members so that each blade projects acrossthe blade chamber as it passes through the part of the blade chamber notoccupied by an abutment but recedes into and is wholly contained in itsrecess during its passage past the abutment, and means for placing theleading end of each blade recess, during its passage pastanabutment,first in communication with the outlet side of the bladechamber andthen, while both ends of the recess lie opposite theabutment, in communication with the trailing end of the recess.

6. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of that blade chamber, the two radially opposed peripheries of.the blade chamber being constituted by parts of one of the two members,an abutment rigid with the other of the two membersand extending acrossthe blade chamber between inlet and outlet ports, blades of part-annularcross-section rotatably mounted in part-annular recesses in one of theradially opposed peripheries and each capable of projecting therefromacross the blade chamber to make a substantially fluid-tight seal withthe other periphery or of lying wholly in its recess according to itsrotational position, the periphery of the blade chamber opposite eachblade recess being provided with a groove whose surface is concentricwith and has the same radius of ourvature as the outer surface of theblade recessso as to provide area sealingv between the blade and thisgroove, means for causing continuous rotation of the blades intheir'recesses during relative rotation of the two 'members so that eachblade projects across the blade chamber as it passes through the part ofthe blade chamber not occupied by an abutment but recedes into and iswholly contained in its recess during its passage past the abutment,'andmeans for placing the leading end of each blade recess, during itspassage past an abutment, first in communication with the outlet side ofthe blade chamber and then, while both ends of the recess lieoppositethe abutment, in communication with the trail- I the member not carryingthe abutment, each blade being capable of projecting across the bladechamber to make an approximately fluid-tight seal with the oppositeperiphery or of lying wholly within its recess according to itsrotational position, and means for causing continuous rotation of theblades in their recesses during relative rotation of the two memberssothat each blade projects across the blade chamber as it passes throughthe part of the blade chamber not c,- cupied by an abutment but recedesinto and is wholly contained in its recess during its passage past theabutment, those parts of the periphery containing the blade recesseswhich lie between the ends of each blade recess being slightly reducedin diameter as compared with the remaining parts of this periphery.

8. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of that blade chamber, the two radially opposed peripheries ofthe blade chamber being constituted by parts of one of the two members,an abutment rigid with the other of the two members and extending acrossthe blade chamber between inlet and outlet ports, blades of part-annularcross-section rotatably mounted in part-annular recesses in one of theradially opposed peripheries and each capable of projecting therefromacross the blade chamber to make a substantially fluid-tight seal withthe other periphery or of lying wholly in its recess according to itsrotational position, and means for-causing continuous rotation of theblades in their recesses during relative rotation of the two members sothat each blade projects across the blade chamber as it passes throughthe part of the blade chamber not occupied by an abutment but recedesinto and is wholly contained in its recess during its passage past theabutment, those parts of the periphery containing the blade recesseswhich lie between the ends of each blade recess being slightly reducedin diameter as compared with the remaining parts of this periphery.

9. A rotary engine comprising two members which enclose between them anannular blade chamber and 'are' rotatable relatively to one an'-' otherabout the axis of that blade chamber, the 7 projecting therefrom acrossthe blade chamber tog'make a substantially fluid-tight seal with theother periphery or of lying wholly in its recess according to itsrotational position, the periphery of the blade chamber opposite eachblade recess being provided with a groove whose surface is concentricwith and has the same radius of ourvature as the outer surface of theblade recess so as to provide area sealing between the blade and thisgroove, and means for causing continuous rotation of the blades in theirrecesses during relative rotation of the two members so that each bladeprojects across the blade chamber as it passes through the part of theblade chamber not occupied by an abutment but recedes into and is whollycontained in its recess during its passage past the abutment, thoseparts of the periphery containing the blade recesses which lie betweenthe ends of each blade recess being slightly reduced in diameter ascompared with the remaining parts of this periphery.

10. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of this blade chamber, at least one abutment rigid with one ofthe members and extending across the blade chamber between inlet andoutlet ports, blades each of which is of part-annular cross-section andis rotatably disposed in a part-annular recess in one of the radiallyopposed peripheries of the blade chamber so that portions of the memberin which the part-annular recesses are formed extend axially into theblades, said one periphery being carried by the member not carrying theabutment, each blade being capable of projecting across the bladechamber to make an approximately fluid-tight seal with the oppositeperiphery or of lying wholly within its recess according to itsrotational position, blade supporting bearings disposed at least partlywithin those portions of the member containing the blade recesses whichextend axially into the blades, and means for causing continuousrotation of the blades in their recesses during relative rotation of thetwo members so that each blade projects across the blade chamber as itpasses through the part of the blade chamber not occupied by an abutmentbut recedes into and is wholly contained in its recess during itspassage past the abutment.

11. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of this blade chamber, at least one abutment rigid with one ofthe members and extending across the blade chamber between inlet andoutlet ports, blades each of which is of part-annular cross-section andis rotatably disposed in a part-annular recess in one of the radiallyopposed peripheries of the blade chamber, this periphery being carriedby the member not carrying the abutment, each blade being capable ofprojecting across the blade chamber to make an approximately fluid-tightseal with the opposite periphery or of lying wholly within its recessaccording to its rotational position, means for causing continuousrotation of the blades in their recesses during relative rotation of thetwo members so that each blade projects across the blade chamber as itpasses through the part of the blade chamber not occupied by an abutmentbut recedes into and is wholly contained in its recess during itspassage past the abutment, and a non-return valve closing the fluidoutlet and disposed inclose proximity thereto, the side of the abutmentadjacent to the outlet having a contour which conforms closely to thepath traversed by the trailing edge of each blade as itpasses across theblade chamber into its recess preparatory to passing the abutment.

12. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of that blade chamber, the two radially opposed peripheries ofthe blade chamber being constituted by parts of one of the two members,an abutment rigid with the other of the two members and extending acrossthe blade chamber between inlet and outlet ports, blades of part-annularcross-section rotatably mounted in part-annular recesses in one of theradially opposed peripheries and each capable of projecting therefromacross the blade chamber to make a substantially fluid-tight seal withthe other periphery or of lying wholly in its recess according to itsrotational position, the periphery of the blade chamber opposite eachblade recess being provided with a groove whose surface is concentricwith and has the same radius of ourvature as the outer surface of theblade recess so as to provide area sealing between the blade and thisgroove, means for causing continuous rotation of the blades in theirrecesses during relative rotation of the two members so that each bladeprojects across the blade chamber as it passes through the part of theblade chamber not occupied by an abutment but recedes into and is whollycontained in its recess during its passage past the abutment, and anon-return valve closing the fluid outlet and disposed in closeproximity thereto, the side of the abutment adjacent to the outlethaving a contour which conforms closely to the path traversed by thetrailing edge of each blade as it passes across the blade chamber intoits recesses preparatory to passing the abutment.

13. A rotary engine comprising two members which enclose between them anannular blade chamber and are rotatable relatively to one another aboutthe axis of this blade chamber, at least one abutment rigid with one ofthe members and extending across the blade chamber between inlet andoutlet ports, blades each of which is of part-annular cross-section andis rotatably disposed in a part-annular recess in one of the radiallyopposed peripheries of the blade chamber so that portions of the memberin which the part-annular recesses are formed extend axially into theblades, said one periphery being carried by the member not carrying theabutment, each blade being capable of projecting across the bladechamber to make an approximately fluid-tight seal with the oppositeperiphery or of lying wholly Within its recess according to itsrotational position, blade-supporting bearings of the elongated rollertype disposed at least partly within those portions of the membercontaining the blade recesses which extend axially into the blades, andmeans for causing continuous rotation of the blades in their recessesduring relative rotation of the two members so that each blade projectsacross the blade chamber as it passes through the part of the bladechamber not occupied by an abutment but recedes into and is whollycontained in its recess during its passage past the abutment.

ERNEST BOOTH.

